1. Field of the Invention
The present invention relates to a case member for power semiconductor devices, such as rectifiers, thyristors and transistors.
2. Description of the Prior Art
Stud type compression bonded power semiconductor devices of the prior art use high electrical and thermal conductivity metals, as for example, copper, for electrical and thermal contact members of the device, while using higher strength metals, as for example, steel, for the compression members of the device.
The superior electrical and thermal properties of copper are preferred for the metal contact members to obtain optimum performance of a power semiconductor device. Since compression bonding requires a high yield strength material such as steel for compression members, optimum performance devices of the prior art use both copper and steel components to form at least part of the device.